One of major standardization organizations for mobile communication, the 3rd Generation Partnership Project (3GPP) has defined an Evolved Packet System (EPS) and has introduced a Mobility Management Entity (MME) as a network mobility management entity, for future-generation communication. Techniques for providing high-speed communication services by improving a protocol used in a legacy communication system, for example, the 3GPP Non-Access Stratum (NAS) protocol used for 3 G communications in relation to security management were proposed for the future-generation mobile communication system. The proposed security management techniques involve enhanced security management such as performing security mode by introducing the concept of a NAS protocol capable of reinforcing security to the NAS layer, in addition to conventional authentication and security control performed in the NAS layer.
However, NAS protocol-based security management techniques proposed so far have specified no appropriate security procedures for authentication and security reinforcement in support of emergency calls or handover of emergency calls. As a result, it is highly probable that security is not ensured or communication is interrupted during handover of an emergency call. Accordingly, there exists a need for a method for seamlessly supporting authentication, security, and communication between a terminal and a network even during handover in an emergency call situation.